The most common end sections for pipe culverts are the shop-fabricated metal end sections and precast concrete end sections available from pipe suppliers. However, the standard reference works on culvert hydraulics provide little information on their hydraulic performance. The hydraulic characteristics of common flared end sections were recently investigated in model tests conducted at the University of Kansas for the Kansas Department of Transportation. Inlet-control rating curves were developed and entrance-loss coefficients for metal and concrete flared end sections of all sizes were determined. The hydraulic effects of floating debris were investigated and some potential design improvements tested. Under inlet control, standard flared end sections perform much better than mitered pipes, slightly better than headwalls with sharp inlet edges, and slightly worse than headwalls with grooved or rounded inlet edges. The concrete flared end sections are slightly more efficient than the metal end sections. Entrance-loss coefficients for flared end sections range from 0.24 to 0.30. Floating debris has little effect on the hydraulic performance of the flared end sections under inlet control. However, an accumulation of debris alters the flow pattern in a way that can cause a shift from inlet control to full flow, a more efficient operating condition. The hydraulic performance of a flared inlet can be improved by adding several bars across the top third of the inlet opening. These "flow bars" have the same beneficial hydraulic effects as an accumulation of debris at the inlet.


  • English

Media Info

  • Features: Figures; References; Tables;
  • Pagination: p. 72-79
  • Monograph Title: 1993 Midwest floods and water quality best management practices
  • Serial:

Subject/Index Terms

Filing Info

  • Accession Number: 00713561
  • Record Type: Publication
  • Files: TRIS, TRB
  • Created Date: Nov 16 1995 12:00AM